1. Field of the Invention
The present invention relates to a thermoelectric generating electronic device such as a wrist watch, etc., an electronic device such as a table clock, a wall clock, a page, etc. Having a thermoelectric generator.
2. Description of the Related Art
The main current of a thermoelectric generating electronic device, e.g., a wrist watch is now an electronic type wrist watch. A silver oxide battery, a lithium battery, etc. Are used as a power source of this electronic wrist watch.
However, these batteries are articles of consumption so that periodic exchange is required and limited resources of the earth are consumed.
Therefore, a wrist watch having an electricity generating mechanism therein instead of these batteries is researched.
For example, a solar battery for converting optical energy, mechanical electricity generation utilizing gravitational energy, or thermoelectric generation utilizing the Seebeck effect based on a temperature difference, etc. are known as an electricity generating system of this wrist watch having the electricity generating mechanism therein. Wrist watches using the solar battery and the mechanical electricity generation among these electricity generating systems are already used practically.
When a thermoelectricity generating system is utilized, the thermoelectric generating electronic device utilizes the difference between a body temperature (a high temperature portion) transmitted to the thermoelectric generating electronic device through an arm and a temperature of the outside air (a low temperature portion) around the thermoelectric generating electronic device.
However, the conventional thermoelectric generating electronic device has problems in thermal conductivity from the high temperature portion to a heat receiving portion of a thermoelectric generator, thermal conductivity from a heat radiating portion of the thermoelectric generator to the low temperature portion, etc. Further, a problem exists in that the above temperature difference sufficient to generate required electric energy by the thermoelectric generator cannot be obtained.
In particular, after the thermoelectric generating electronic device is mounted to an arm, a rear cover of the thermoelectric generating electronic device is rapidly warmed by the body temperature for some time. In contrast to this, a drum or a bezel of the thermoelectric generating electronic device is cold. Therefore, the temperature difference between the heat receiving portion and the heat radiating portion of the thermoelectric generator is large. However, the bezel gradually rises in temperature by thermal conductivity so that the temperature difference is gradually reduced.
When the thermoelectric generating electronic device is detached from the arm, the heat receiving portion and the heat radiating portion of the thermoelectric generator are approximately simultaneously cooled by heat radiation so that the temperature difference becomes small. Therefore, a problem exists in that no thermoelectric generator can almost generate electric energy.